Baffling for boilers



J. B. CRANE BAFFLING FOR"BOILERS 1923 3 Sheets-Sheet 2 Filed Oct. 24

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J. B. CRANE BAFFLING FOR BOILERS Filed Oct. 24. 1923 s Sheets-Shet s EllPatented Oct. 20, 1925.

UNITED STATES PATENT OFFICE.

JOSEPH B. CRANE, 0]! PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO GEORGE '1.LADD,

OI PITTSBURGH, PENNSYLVANIA.

BAI'FLING FOB BOILERS.

Application filed October 24, 1923. Serial No. 670,489.

To all whom it may concern:

Be it known that I, JOSEPH B. CRANE, residing at Pittsburgh, in thecounty of Allegheny and State ofPennsylvania, a citizen of the UnitedStates, have invented or discovered certain new and useful Improvementsin Baffling for Boilers, of which ima' provements the following is aspecification.

It is the usual practice to so construct and arrange the baflies inboilers that the direction of flow of gases through the boiler isreversed or changed through an angle of approximately one hundred andeighty degrees, twov or three times. This reversal causes a greaterretardation in the rate of flow than the tubes themselves, and hence inconstructing a boiler provision must be made either by the constructionof the stack or the employment of exhaust fans for producing asufficient drop of pressure between the furnace and the gases outlet, toovercome not only the retardation due to the resistance encountered bythe ases flowing across and along the tubes and that due to the reversalof the flow when operating at normal rating, but also to cause theincreased flow necessary to operate the boiler above rating. Theconstruction of a stack capable of overcoming the necessary drop ofpressure orthe employment of a fan of suficient capacity, adds greatlyto the cost .of installation. It is of course possible to obtain anincrease of rating without increasing the volume or weight of gasesflowing through the boiler, by increasing the temperature of the gasesgenerated. This method is decidedly objectionable as it involves a:great increase in the amount of fuel consumed, and a consequentincrease in operating expenses.

The invention described herein has for its object the so baffling of theboiler that eiiicient contact of the hot gases with the heat ingsurfaces is attained without reversal in the direction of flow of thegases, and with slight change in the direction of flow. The invention ishereinafter more fully described and claimed.

. In the accompanying drawings forming apart of this specification Fig.1 is a sectional elevation of 'a vertical water tube boiler baflied asdescribed andclaimed herein; Fig. 2 is a sectional planview on a planeindicated by the line IIII Fig. 1; Figs. 3, 4:, 5, and 6 are detailviews showing different arrangments of battles and manner ofconstructing the same.

In combining the improvenwnt claimed herein with vertical Water tubeboilers, the

bafflesextend from the lower to the upper drums or the entire length ofthe tubes, and parallel therewith. In the embodiment of the inventionshown herein in Fig. 1, the battles are arranged in line with the lastseries of tubes forming the several banks of tubes 1, 2, 3,buttheinvention claimed herein is not limited to any specific location ofthe baflies transverse of the direction of flow of the gases from thecombustion chamber to the stack. To permit of the-flow of gases to thestack, opening or ports 4 are formed through the baiiies. As is Wellknown to those skilled in the art, a boiler is at times operated atnormal rating and frequently considerably above normal rating, and whenoperated above rating the volume of gases generated and passed throughthe boiler is very much greater than when the boiler is operated atnormal rating. Hence the openngs 4 through the first baffle or the onead- ]acent to the combustion chamber, are made of such dimensions as to.permit the passage of gases which would be generated when the boi er isoperated at an average rating be tween normal and the highest rating atwhich the boiler is designed to be operated. In order to break up thestreams of gases flowing through the openings in a battle, and sodivert'such streams as to ensure the circulation ofthe gases among thetubes the openings in succeeding baffles are'arranged out of alinementwith the openings the preceding baffie. As for example,'in theembodiment shown in Figs. 1 and 2, the openings in the second baffle arearranged out of alinement with the openings in the first battle, and theopenings in the third are arranged out of alinement with the openings inthe second bafie. i

As the gases flowing between the tubes are progressively cooled andtheir volumes decreased, the total area of the openings in eachsucceeding baffle are preferably proportionally less than that of theopenings in the preceding baflle. In vertical boilers, and in the termvertical boilers are included both the Wicks Sterling and the Ladd orMilne types, the fuel bed i's adjacent to the lower ends of the firstbank of tubes, as shown in Fig. 1, andjin order to prevent a tendency ofthe gases to short circuit through the lower openings in the batlle,such openings may be made of relatively small areas and the areasprofrirssively larger towards the upper ends ot' the battles. Thisproportioning of the areas of the openings in connection with thetendency of the hot gases to pass upward. would tend to draw the gasesaway from the smaller openings of the lower end, but as the openings atthe upper ends will permit of the passage of only certain proportionsofthe volumes generated, there will always be an etficient flow oi gasesthrough the lower openings. Such a construction of bullies and relativeproportioning of openings in each will ensure a substantially unitormflow of gases and consequently equal application of heat in all pointsalong the length of the tubes in front of such baflle.

As shown in Figs. 3 and ti, the bafiies may be formed by filling thespaces between alternate pairs of tubes with suitable material such torexample as wedge shaped blocks 5, as shown in Fig. (3. In such aconstruction the openings for the passage of gases will extend theentire distance be-- tween'the drums. But as in such construction it maybe ditlicult to control the distribution of the gases vertically, it isp re-' ferred to construct the battles as shown in Fig. As shownthereon, the spaces between all of the tubes; oi a row or series are solilledor closed as to have openings at suitable intervals horizontallyand vertirally. A desirable means for forming sucla a baille consists inemploying wedge shapec blocks (3. These blocks are formed with groovesin one edge so as to fit around the tubes while the opposite edge isinclined. These blocks are so coii'structed that when placed in reversedposition with their inclined faces in contact and their ends inalinement, the combined width of the blocks will be greater than thedistance between walls of ad iacent tubes. In arranging these blocks inposition, a block is inserted between adjacent tubes with its larger endresting on the lower drum and the groove in its edge engaging a tube. A.second block in reversed position is then inserted between the firstblock and the other tube, but as the combined widths of the blocks isgreater than the distance between the tubes, this second tube will notmove down so that its lower end will bear on the drum,'hence there willbe an opening. formed. The third block 6 will be arranged so that itslarger end will rest on the larger end of the block 6" and the block 6inserted in the same manner as the block 6*, thereby forming an openingof double the area of the opening at the lower end of the block 6. Bythus forming the battle, a plurality of openings are formed alternatinghorizontally and vertically. In case smaller openings are desired, theblocks forming the battle may be arranged as shown in F 4. As shown inFig. 5, one of the members as 7 forming a pair of blocks may be madeshorter than the mem her 6. a

It is characteristic of the improvement claimed herein that although thegeneral direction of flow of gases from the combustion chamber to thestack is at right angles to the tubes forming the heating surfaces,their lines of movement are more or less directed from straight lines bythe relative positions of the openings in the baflles, and hence theirflow may be more correctly termed sinuous but in no case Will thelateral diversion from the general line of flow approach a reversal ofthe direction of flow.

I claim herein as my invention:

' 1. A vertical water tube boiler having in combination vertical banksof tubes, a combustion chamber and an outlet for gases so arranged onopposite sides of the banks of tubes that the line of flow of hot gaseswill be at an angle to the tubes and baflles extendin parallel with andthe entire Widths of the banks of tubes and having openings therethroughthe openings in adjacent baffles being out of alinement and the area ofsaid openings increasing from points adjacent to the combustion chamber.I

2. A vertical water tube boiler having in combination therewith verticalbanks 0:" tubes, combustionchamber and an outlet for the gases soarranged on opposite sides of the bank of tubes that a line of flow ofthe gases will be at an angle to the tubes, and. battles consisting of aplurality of pairs of longitudinally tapering blocks arranged betweenadjacent tubes, a block of each pair being spaced from the verticallyalined block on the adjacent pair.

In testimony whereof, I have hereunto set my hand.

JOSEPH B. CRANE.

